Tetrofosmin is a diagnostic agent used to assess areas of reversible myocardial ischemia in the presence or absence of infracted myocardium and is also used to assess ventricular function.
PHYSICAL HALF-LIFE & TARGET ORGANS
The physical half-life of technetium, Tc99m, is 6 hours and has a principal radiation emission of gamma photons with a mean energy of 140 KeV.
Estimated Absorbed Radiation Dose (Technetium Tc99m Tetrofosmin Injection) | Absorbed radiation dose |
| Exercise | Rest |
| Target organ | rad/mCi | µGy/MBq | rad/mCi | µGy/MBq |
| Gall bladder wall | 0.123 | 33.2 | 0.180 | 48.6 |
| Upper large intestine | 0.075 | 20.1 | 0.113 | 30.4 |
| Bladder wall | 0.058 | 15.6 | 0.071 | 19.3 |
| Lower large intestine | 0.057 | 15.3 | 0.082 | 22.2 |
| Small intestine | 0.045 | 12.1 | 0.063 | 17.0 |
| Kidney | 0.039 | 10.4 | 0.046 | 12.5 |
| Salivary glands | 0.030 | 8.04 | 0.043 | 11.6 |
| Ovaries | 0.029 | 7.88 | 0.035 | 9.55 |
| Uterus | 0.027 | 7.34 | 0.031 | 8.36 |
| Bone surface | 0.023 | 6.23 | 0.021 | 5.58 |
| Pancreas | 0.019 | 5.00 | 0.018 | 4.98 |
| Stomach | 0.017 | 4.60 | 0.017 | 4.63 |
| Thyroid | 0.016 | 4.34 | 0.022 | 5.83 |
| Adrenals | 0.016 | 4.32 | 0.015 | 4.11 |
| Heart wall | 0.015 | 4.14 | 0.015 | 3.93 |
| Red marrow | 0.015 | 4.14 | 0.015 | 3.97 |
| Spleen | 0.015 | 4.12 | 0.014 | 3.82 |
| Muscle | 0.013 | 3.52 | 0.012 | 3.32 |
| Testes | 0.013 | 3.41 | 0.011 | 3.05 |
| Liver | 0.012 | 3.22 | 0.015 | 4.15 |
| Thymus | 0.012 | 3.11 | 0.009 | 2.54 |
| Brain | 0.010 | 2.72 | 0.008 | 2.15 |
| Lungs | 0.008 | 2.27 | 0.008 | 2.08 |
| Skin | 0.008 | 2.22 | 0.007 | 1.91 |
| Breasts | 0.008 | 2.22 | 0.007 | 1.83 |
Dose calculations were performed using the standard MIRD method (MIRD Pamphlet No.1 (rev),Society of Nuclear Medicine, 1976).
Effective dose equivalents (EDE) were calculated in accordance with ICRP 53 (Ann. ICRP 18 (1-4),1988) and gave values of 8.61 × 10-3 mSV/MBq and 1.12 × 10-2 mSV/MBq after exercise and rest, respectively.